本文主要討論道家的知識論。但由於道家義理系統所終極嚮往的乃是超越之「道」，故順「為道日損」的方向，道家總消極地視知識出於經驗之主觀，然則，客觀的知識不能立。然而，作為圓教的一個典型，道家亦不能排除或否定知識，因此，基於系統之圓滿的要求，道家順「為學日益」的方向於知識亦有所安排，此即完成其關乎現象界的知識之「執的存有論」。此一執的存有論乃是以「成心」作為主體主觀方面的認知機能，而以「八畛」作為成心所先驗地自發的純粹形式概念，如是乃於主體的主觀之中取得了一個相對的客觀性，而知識得以積極地被建立。不過，成心亦非知識之最後的根源，依道家義理之究竟，成心乃是依「道心」之自我坎陷而辯證地開顯出者，故，道心才是那最後的根源。因此，依道心而有「無執的存有論」，依道心之自我坎陷而轉出成心，則有關知識之「執的存有論」亦得以被融攝進來，如此即完成一有執、無執進退自如之「兩層存有論」的體系。此即《莊子．大宗師》所謂：「庸詎知吾所謂天之非人乎？所謂人之非天乎？」這才是道家對於知識之終極的說明。

　　　　　The purpose of this artical is to probe deeply into Taoist epistemology. Because the ultimate goal of Taoist philosophy is transcendental "Tao", Taoismnegatively regards knowledge as derive from empirical subjectivity. Naturally Taoism is convinced that subjective knowledge cannot stand firmly. But, as a type of "perfect teaching", Taoism cannot eliminate or negate knowledge. In order to meet the perfect need of Taoist philosophy, Taoism also deals with knowledge tremendously well. That is to say Taoism has accomplished its "attachment ontology" which is about phenomenal knowledge. As for this "attachment ontology", "haditual-mind" acts as subjective recognition faculty of subject; and "8 categories" is spontaneous, and this pure formal concept comes from "habitual-mind" a priori. Thus, relative objectivity is derived from subjectivity of subject. And knowledge is positively established. However, "habitual-mind" is not the final source of knowledge. According to the ultimate of Taoist philosophy, "habitual-mind" is dialectically revealed and manifested on the basis of "the self-negation of Taoist-mind". Therefore "Taoist-mind" is the final source. Through "Taoist-mind" exist "non-attachment ontology", and "habitual-mind" comes into being through the self-negation of Taoistmind, so the "attachment ontology" of knowledge is adopted. In this way, a system of infinitely free "bi-level ontology" is accomplished. This is the ultimate explanation of knowledge by Taoism.